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| #45359 (Received by flhurricane at: 4:40 PM 11.Sep.2005) TCDAT1 HURRICANE OPHELIA DISCUSSION NUMBER 22 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 5 PM EDT SUN SEP 11 2005 MAXIMUM SURFACE WINDS MEASURED BY THE STEPPED-FREQUENCY RADIOMETER ON BOARD A NOAA HURRICANE HUNTER AIRCRAFT WERE 61 KT AND PEAK FLIGHT-LEVEL WINDS WERE 77 KT. USING A BLEND OF THESE DATA...THE CURRENT INTENSITY IS ADJUSTED DOWNWARD TO 65 KT. BECAUSE OF THE INFLUENCE OF UPWELLED COOLER WATERS AND DRIER AIR TO THE WEST...NO INTENSIFICATION IS FORECAST FOR THE NEXT DAY OR SO. SOME RE-INTENSIFICATION MAY OCCUR BY 48-72 HOURS DUE TO THE ENERGIZING EFFECT OF THE GULF STREAM AND A MODIFICATION OF THE AIR MASS. ALTHOUGH THE ENVIRONMENT DOES NOT APPEAR TO FAVOR A LARGE INCREASE IN STRENGTH...INTENSITY PREDICTIONS CAN EASILY HAVE ERRORS OF 1 SAFFIR-SIMPSON CATEGORY IN 2-3 DAYS. THE OFFICIAL WIND SPEED FORECAST IS AGAIN RATHER SIMILAR TO THE SHIPS GUIDANCE. COOLER WATERS ARE LIKELY TO CAUSE WEAKENING BY DAYS 4-5. THE CENTER DRIFTED A LITTLE WESTWARD OR WEST-SOUTHWESTWARD OVER THE PAST FEW HOURS...BUT SO FAR THE MOVEMENT IS STILL QUASI-STATIONARY. OPHELIA REMAINS TRAPPED BETWEEN HIGH PRESSURE CELLS. THE BLOCKING HIGH OVER THE OHIO VALLEY IS PREDICTED TO BE BROKEN UP IN 2-3 DAYS BY A LARGE 500 MB TROUGH PROGRESSING FROM THE CENTRAL UNITED STATES. THIS SHOULD ALLOW OPHELIA TO EVENTUALLY MOVE ON A NORTHWARD AND THEN NORTHEASTWARD TRACK...AS THE TROUGH BECOMES THE DOMINANT STEERING FEATURE LATE IN THE PERIOD. TRACK MODEL GUIDANCE IS SOMEWHAT DIVERGENT. THE GFS HAS SHIFTED FARTHER TO THE LEFT AND SHOWS LANDFALL OVER SOUTH CAROLINA WHILE THE U.K. MET MOVES THE SYSTEM VERY SLOWLY FOR A FEW DAYS AND THEN TAKES IT NORTHEASTWARD JUST OFF THE OUTER BANKS. THE FSU SUPERENSEMBLE KEEPS OPHELIA WELL EAST OF THE COAST. THE OFFICIAL FORECAST SHOWS A MORE WESTWARD TRACK DURING THE FIRST 1-2 DAYS BUT THEN TURNS THE SYSTEM TO THE NORTH AND NORTHEAST. THIS IS FAIRLY CLOSE TO THE LATEST GFS AND NOGAPS SOLUTIONS...AND ABOUT IN THE MIDDLE OF THE GUIDANCE SUITE. THE SLIGHTLY MORE WESTWARD TRACK AND A SLIGHT EXPANSION OF THE WIND FIELD BASED ON SHIP...BUOY...AND AIRCRAFT DATA...DICTATE THE ISSUANCE OF A TROPICAL STORM WARNING FOR A PORTION OF THE SOUTH CAROLINA AND NORTH CAROLINA COASTS AT THIS TIME. FORECASTER PASCH FORECAST POSITIONS AND MAX WINDS INITIAL 11/2100Z 31.5N 76.0W 65 KT 12HR VT 12/0600Z 31.7N 76.5W 65 KT 24HR VT 12/1800Z 31.9N 77.1W 65 KT 36HR VT 13/0600Z 32.4N 77.3W 65 KT 48HR VT 13/1800Z 32.9N 77.3W 70 KT 72HR VT 14/1800Z 34.5N 76.5W 70 KT 96HR VT 15/1800Z 37.0N 75.0W 50 KT 120HR VT 16/1800Z 41.0N 70.0W 40 KT |
